Benzaldehyde → Perfluorophenyl 5-(1-benzylpyrrolidin-2-yl)naphthalene-2-sulfonate

Participants

Reaction Steps

A 10-mL round-bottom flask was charged with perfluorophenyl 5-(pyrrolidin-2-yl)naphthalene-2-sulfonate 2,2,2-trifluoroacetate (from STEP 2 of INTERMEDIATE KK) (56.79 mg, 0.102 mmol), DCE (509 μl), and benzaldehyde (31.0 μl, 0.306 mmol) to give a suspension. Sodium triacetoxyborohydride (43.2 mg, 0.204 mmol) was added, followed by an additional portion of DCE (509 μl) to thin the mixture. After 1 h, a saturated aq. Rochelle's salt solution (3 mL) and DCM (2 mL) were added, and the resulting mixture was stirred vigorously for 3 h. The mixture was diluted with water and extracted with DCM (3×). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated. The residue was purified by chromatography on a 12-g with 0 to 40% EtOAc/Heptane to give perfluorophenyl 5-(1-benzylpyrrolidin-2-yl)naphthalene-2-sulfonate (52.93 mg, 0.099 mmol, 97% yield) as a clear oil: 1H NMR (400 MHz, DMSO-d6) δ ppm=8.86-8.70 (m, 2H), 8.22-8.10 (m, 2H), 8.00 (dd, J=2.2, 9.1 Hz, 1H), 7.81-7.73 (m, 1H), 7.33-7.26 (m, 4H), 7.25-7.17 (m, 1H), 4.20 (t, J=8.2 Hz, 1H), 3.77 (d, J=13.2 Hz, 1H), 3.20 (d, J=13.2 Hz, 1H), 3.13-3.02 (m, 1H), 2.48-2.40 (m, 1H), 2.33 (q, J=9.2 Hz, 1H), 1.93-1.82 (m, 2H), 1.78-1.60 (m, 1H); m/z (ESI) 534.4 (M+H)+.

Provenance & Evidence